Typically, subsea systems utilize high voltage subsea cables to electrically connect subsea equipment. Often, subsea cables comprise an outer shielding layer. Some types of outer shielding layers allow controlling dielectric stress on the cable insulation of the subsea cable; then, the outer shielding layer is sometimes referred to as screen. Typical examples of outer shielding layers comprise a foil wrap, copper tape, multi-strand braid, a solid lead layer, metallic material, or semi-conductive material. For effective operation, the outer shielding layer is connected to Ground (Earth) via an earth link wire.
Establishing the electrical connection between the earth link wire and the outer shielding layer can be challenging. This is due to the ductile nature and plastic deformation properties of the material thereof.
Different reference implementations of establishing the electrical connection between the earth link wire and the outer shielding layer exist.
One example of establishing such an electrical connection by means of a subsea connector 20 according to reference implementations is shown in FIG. 1. Here, the earth link wire 121 is held an electrical connection with the outer shielding layer 112 of the subsea cable 111 by trapping the earth link wire 121 within windings or revolutions of a constant force coil 191. A so-called earth breakout boot 192 protects the connector 20 against environmental influences.
However, such techniques face certain drawbacks. E.g., while the constant force coil 191 can accommodate changes in the diameter of the subsea cable 111 to a certain extent, movement of the subsea cable 111 can cause friction in between the outer shielding layer 112 and the constant force coil 191. Abrasion or chaffing of the outer shielding layer 112 may result. Further, the earth breakout boot 192 may be susceptible to air entrapment. Air entrapment can cause distortions to the outer shielding layer 112 due to differential pressure within the connector 20 during operation. Furthermore, where a plurality of subsea cables 111 is arranged in the vicinity of each other—e.g., in order to connect to one and the same subsea equipment at a given position—it is possible that the significant outer dimensions of the connector 20 require splaying of the subsea cables 20 with respect to each other. Then, a flexibility in the arrangement of the subsea cables is typically limited.
In a further reference implementation, the electrical connection between the earth link wire 121 and the outer shielding layer 112 is provided by techniques such as soldering; the corresponding connector 20 is shown in FIG. 2. Here, a solder ring is formed by solder wire 193. The earth link wire 121 is soldered to the solder wire 193.
However, such techniques as explained above face certain drawbacks. E.g., the connection formed by soldering may have limited durability. E.g., due to cable manipulation in the assembly process and/or due to thermal expansion/contraction, stress can be induced in the corresponding connector causing failure. Again, it is possible that the earth breakout boot 192 is susceptible to air entrapment.